FR2493910A1 - ZIRCONIA AND SILICA BASE AGENT FOR DEEP GEOLOGICAL FRACTURES - Google Patents

Abstract

THE INVENTION RELATES TO THE FIELD OF OIL EXTRACTION. IT CONCERNS, MORE PRECISELY, A GRANULAR SUPPORT AGENT WITH HIGH MECHANICAL STRENGTH, WITH A DENSITY LESS THAN 3250KGM, CHARACTERIZED IN THAT IT CONSTITUTES BALLS FORMED BY FUSION, GRANULATION AND SOLIDIFICATION, CONSISTING OF A DEPARTMENT COMPONENT , BY WEIGHT BASED ON OXIDES, 46 TO 50 PARTS OF ZRO, 54 TO 50 PARTS OF WIS, THE SUM OF ZRO WIS TOTALIZING 100 PARTS, 0 TO 19 PARTS OF ALO AND 0 TO 13.5 PARTS AT LEAST AN OXIDE CHOSEN FROM THE GROUP SHAPED BY MGO, CAD, FEO AND TIO. USE BY OIL TANKERS.

Description

The present invention relates to the field of

  oil extraction and relates to a support agent

  fractures created in the walls of a

geological formations.

  It is well known to perform well stimulation by fracturing the geological layers, for example

  injecting a fluid at high pressure into the

  which one wishes to fracture, then injecting

  solid granules (proppant) for pocketing

the fractures to close.

  Many materials have been proposed. But in

  geological formations at great depth, the exploitation of which

  for the extraction of oil or natural gas is

  veloppe, the constraints on the stacks of

  solid grains are such that many common

  used, particularly silica sand or glass beads, are significantly fragmented. We observe that

  the created fragments decrease the permeability of the fracture.

  As a result, the production of fractured formations decreases.

  It has been observed, moreover, that

  proppants with regard to the solicitations encountered

  countered in this type of operation is not just about

  with the crushing resistance of the grains taken

  vidually. So we looked for proppants

  having a lower case rate in a multilayer bed.

  Retaining agents of alumina or sintered bauxite are presently commercially available. In addition, the Claimant markets an agent

  support consisting of zirconia and silica in

  such portions that the weight ratio ZrO 2 / biO 2 is at least 1.5, alumina and sodium oxide being

  optionally included (see the French patents

  2 506 327 and 2 359 274 and the United States patent of

  No. 4,072,193). All commercially available high strength proppants have

  high densities of at least 3300 Kg / m3 and

to reach 3800 Kg / m3.

  The injection of proppants with a high volumetric mass creates difficulties of transport to the bottom of the fractures due to their sedimentation rate in the fracturing fluid. It is therefore necessary to employ

  more viscous and dense fluids in order to limit the maximum

  mum sedimentation and allow a progressive placement to the bottom of fractures created. These fluids do not always give the best results (degradation of the fluid, damage of the formation) and are, moreover, very expensive. It would therefore be interesting from a technical and economic point of view to have high proppants

  mechanical resistance for great depths, but of a mas-

  is less than the values encountered with the

  proppants currently available. In addition to

  Because of the lower economic cost of using a less complex fracturing fluid, lower density of proppants will result in lower velocity

  sedimentation and thereby contribute to a better

  the effectiveness of the operation by favoring the placement of

  support in a larger proportion of the fracture

  re. In a fluid, the sedimentation rate of a particular

  the solid is proportional to the difference of the masses

  luminescence of the solid and the carrier fluid. Other things being equal, the reduction in the density of a proppant from 3800 to 3200 Kg / m3 will result in a decrease in the sedimentation rate of 21% in a fluid with a density of 1000 Kg / m3 and The object of the invention is to provide a proppant having a high mechanical strength, especially in a bed of 24% in a fluid having a density of 1300 Kg / m3.

  multilayer, with a density of less than 3250 kg / m3.

  More particularly, the invention relates to a granular proppant with high mechanical strength, with a density of less than 3250 Kg / m3, characterized in that it consists of beads formed by melting, granulating and solidifying a composition. starting material comprising, by weight on the basis of the oxides, 46 to 50 parts of ZrO 2, 54 to 50 parts of SiO 2, the sum ZrO 2 + SiO 2 totaling 100 parts, 0 to 19 parts of Al 2 O 3 and O to 13.5 parts of at least one oxide

  selected from the group consisting of MgO, Cao, FeO and TiO2.

  Preferably, the starting composition comprises 47.1 to 48.7 parts of ZrO2, 52.9 to 51.3 parts of 8102, the sum of ZrO2 + SiO2 totaling 100 parts, 8.2 to 1b, 9 parts A1203 and 4.1 to 8.5 parts of at least one selected oxide

  in the group formed by MgO, CaO, FeO and TiO2.

  The composition of the balls is substantially identical

  to that of the starting composition.

  The proppants whose composition falls within the broad range defined above have a behavior in the laboratory tests described below equivalent to that of known high strength proppants up to

  effective stresses of 70 MPa.

  Proppants whose composition falls

  in the preferred range defined above have volumetric masses

  between 3150 and 5250 Kg / m3 and behavior

  equivalent to that of high-strength proppants

  currently known, up to the actual constraints of

  100 MPa, which is higher than the actual

  in the deepest deposits.

  The manufacture of the balls of the invention takes place from

  conventional way0 The charge of constituent or precursor oxides

  of these (natural mineral

  silicates) can be melted in an electric oven.

  than. A net of molten material is granulated by blowing (with air or steam). Thus, beads having a size of 0.1 to 4 mm are obtained, the most appropriate granulometries

  for application as a proppant are located in

be 0.25 and 2.0 mm.

  The production of ZrO2 and SiO2 beads

  only with a ZrO2 / Si0241 ratio, however,

  ficultés, as indicated in French Patent 2,320,276 or US Patent No. 4,106,947. Also, in order to avoid the problems encountered with the manufacture of beads consisting of ZrO 2 and SiO 2 alone, it is recommended starting from a composition comprising at least 4 parts and also preferably at least 1 part of at least one oxide selected from the group consisting of MgO, CaO, FeO and TiO 2. Advantageously, we will start from a composition containing 8.2 to 16.9 parts of 1203 and 4.1 to 8.5 parts of MgO, CaO, FeO and / or TiO2, per 100 parts of the total ZrO2 + SiO2. The incorporation of these additives, especially in the preferred range above, makes it easier to

  the fusion of the starting composition and allows a

  in the form of mostly spherical particles with

  a good return. Also, the preferred starting composition

  to produce in the most economical way (good

  multi-bed bedrock

  The following nonlimiting examples are given in order to illustrate the invention. EXAMPLES 1 to 8 and COMPARATIVE TESTS A to D:

  It has been prepared by melting, granulation and solidification.

  substantially spherical balls having the composition

  and the density given in Table 1 are

  which also indicates the value of certain relationships between

components.

  Beads according to Examples 1 to 8 and Controls A to D having a particle size in the range of 0.425 to 1.0 mm were subjected to a conductivity measurement test and a breakage measurement test. The balls of the examples

  1 and 2, although falling within the scope of the invention,

  difficulties of manufacture (poor performance), this

  which makes them unattractive economically.

  The conductivity measurement test is a standard test that consists of measuring the permeability k of a

  layer of the proppant, having an initial thickness

  the h (6 mm), subjected to a pressure p, vis-à-vis the passage

  of air pressure at 2000. The conductivity is equal to the

  duit kh and is measured in Darcometers. At p = 70 MPa, the

  The activity of agents 1 to 8 is from 0.95 to 1.1 Darcy-meter (substantially constant value) and is similar to that of commercial C and D controls. Agents A and B, on the other hand, have a conductivity which is as low as p = 30 MPa and, for p = 70 MPa,

  have a conductivity of less than 0.2 Darcy-meter.

  The preferred agents 4, 5, 6 and and the controls 0 - 5 - and D of the trade were tested up to p = 100 MPa, their respective conductivities at this pressure of compaction are

  equal to 0.78; 0.76; 0.72; 0.82; 0.68 and 0.78.

  The conductivity of the proppants of the in-

  vention therefore compares favorably with that of the best products of commerce, even though

  density is significantly lower.

  The test for measuring the breakage rate consists of

  put a multilayer bed of the agent to be tested, placed in a 50.8 mm diameter steel cylinder closed by a punch, at a pressure of 70 or 100 MPa according to the following program: rise in pressure in 1 minute then maintenance pressure for 2 minutes. The agent is then sieved through a 0.425 mm mesh size sieve. The percentage of material passing through the sieve is the breakage rate. In the test at 70 MPa, the breakage rates are as follows: Agent 1 2 3 4 5 6 7 8 AB a D Rate of 0.6 1.8 1.9 0.9 0.5 0.6 0, 8 0.4 19.1 9.3 0.5 0.5 breaks, In the 100 MPa test, the breakage rates are as follows: Agent 4 5 6 8 a D Rate 2.1 2,9 2 , 5 1,4 3,5 3,2 breaks,%

  The resistance of the agents of the invention, in particular

  bind preferred agents, to compaction under high pressure favorably compares with that of the best

trade support agents.

  Tests under 100 MPa subject the agents to constraints higher than those actually encountered in

the deepest deposits.

TABLE 1

  Composition, in parts by weight on the basis of the oxides Weight ratio (Kg / m3) ZrO 2 49.8 ZrO 2 SiO 2 50.2 - 5232 IO SiO 2 ZrO 2 SiO 2 Al 2 O 3 TiO 2 Pe O 46.3 53.65 0 , 81 0.20 0.20 ZrO

= 0.864

A1203 = 0.015

SiO2 TiO2 + FeO

= 0.008

  SiO 2 ZrO 2 49.2 ZrO 2 0.30 O 50.8 S0 = 0.969 3 Zr 2 0.2 SiO 2 O 31

A1203 4.7 A1203 009

3o i = 0.093 SiO 2 ZrO 2 SiO 2

A12 03

MgO 48.7 51.3 9.3 4.2 ZrO2

= 0.949

A1203 SiO2 MgO = 0.082 SiO2

= 0.181

nb ms a vo o

Examples

  ! TABLE I (cont.) Composition, in parts by weight based on the oxides Weight ratio Density (Ig / m3) ZrO 2 47.1 ZrO 2 SiO 2 52.9 S 2 = 0.892 gg O = 0106 3180 A1 0160S 2 2 O 2 Ai 0.892 = 0.106 i2 331803 xgOo 5, 6 - i03 = O, 306

,,,. , ..

  ZrO2 zio2 8'O2 Al2O3 TiO2 48.3 51.7, 2 7.5 ZrO2 = 0.934 BiO2 Al0 = O

SO = 0.198

  TiO 2 SiO 2 I -4 I ZrO 2 48; 7 ZrO 2 Zr 2 -0.949 SiO 2 51.3 SiO 2 TiO 2 + FeO 7 Lz 3 ', A2 Si0 = 0.030 330

ALZ0B 03 SO

  TiO2 1.2 = 0.158 FeO 0.3 SiO2 ZrO2 48.7 ZrO2 0.950 8iO2 51.3 - 93 93 b = CaO + TiO2

8 | A1 3 = 0.90 | 3210

  Al205 12.2 0.101 CaO 4.1 SiO2.0 TiO2 1.0 I

Examples

  NOT %; TABLE 1 (cont'd) Composition, in parts by weight on the basis of oxides Ratio by volume (ZrO 2) ZrO 2 41.1 ZrO 2 A * SiO 2 58.9 SiO 0698 A1203 0.6 2 TiO 2 + FeO 290

2 3AI 0 - 0 $ 003 2950

  SiO2 0.1 23 = 0.010 SiO2.0 FeO 0.1 SiO2 - Zro2 Sio2 Al2O3 37.2 62.8 0.5 Si2 SiC2 Zr2 Si92 0.592 0.008 o Co Sintered bauxite beads a (1) 3730

(A1203-- 89.%)

  ZrO2 D (2) zirconia and sili- - = 2.2 beads 3820 SiO2 This product is sold under the brand name "High-Strength Proppant" by the company CARBORUnDUM

COMPANY

  Commercial product sold under the name "E.R. 120 B" by SOCIETE EUROPEENIME DES

REFERENCE PRODUCTS

  Products A and B are experimental products outside the scope of the invention o -h ta

Examples

(1) (2) * i -9 -

Claims (4)

  1. High-strength granular proppant   mechanical composition having a density of less than 3250 kg / m.sup.5, characterized in that it consists of beads formed by melting, granulating and solidifying a starting composition comprising, by weight on the basis of the oxides, to 50 parts of ZrO 2, 54 to 50 parts of SiO 2, the sum ZrO 2 + biO 2 totaling 100 parts, 0 to 19 parts of Al 2 O 5 and 0 to 13.5 parts of at least one oxide selected from the group consisting of MgO, CaO, FeO and TiO2.   2. proppant according to claim 1, characterized in that the starting composition comprises at least minus 4 parts of A1203.   3o proppant according to claim 2, characterized in that the starting composition comprises at   at least 1 part of at least one oxide selected from the group by MgO, CaO, FeO and TiO2.   4. proppant according to claim 1, characterized in that the starting composition comprises 47.1 to 48.7 parts of ZrO2, 52.9 to 51.3 parts of SiO2, 8.2 to 16.9 parts of A1203 and 4.1 to 8.5 parts of at least one oxide   selected from the group consisting of MgO, CaO, FeO and TiO2.   5. A proppant according to any one of   Claims 1 to 4, characterized in that it has a size between 0.25 and 2.0 mm.